Rear cinema speaker correction

Rear cinema speaker correction ..

Why, why, why is there no “out of box” thinking ???
This is what I mean …
A huge London based installer creating a home cinema for a huge client (of “Sir” status) fits rear / side effects speakers in wall. The wall in question is built specifically for the job, forming part of the room’s boundaries and decorated for both acoustic and visual reasons with a fabric finish.


When I asked the installer “what are you going to do about the rear speakers firing through a fabric which is NOT acoustically transparent ?”  their answer actually left me speechless – something of a rarity for me.
The answer was also, probably fine for Mr Jone’s DIY install, involving a big LED tv and a Yamaha processor, but a million miles away from professional, ethical, technically correct or remotely decent for a job where just one of the seats would have cost more than Mr Jone’s entire DIY project.
Here it is … the answer … breath deep ….

“We need to have access to the speakers for service anyway, so the fabric finish panels will have to be removable. So, we demonstrate the system to the client, with the panels “on” and “off”, giving them the choice between aesthetics and sound quality”.

What ….

The installer seems to be saying, to a “Sir client” lets not forget, that he has the choice between:
(1) Sensible audio clarity from the rear effects speakers, but being able to see a black baffle and drivers, in a room which fortunes have been spent on “look” and finishes despite that fact that it actually operates with the lights off.
Or
(2) Audio quality likened to speakers wrapped in a duvet, but  without any visual disturbance to finish.

I can’t tell you how ridiculous this is. Absolutely no thought to correcting rear cinema speakers to account for decorative finishes.

This is the issue …

rear cinema speaker correction frequency response graph.jpgA whole 18dB response dip at 5khz if you have the fabric finish in place covering the speakers

There’s many ways to view this common issue, one would be that:
It’s a cinema, it operates in the dark, the offending devices are behind you, so you don’t really see them anyway, but they are a vital part of the audio make up, so leave them uncovered and visible. Simple.

However, I of course understand that something a “little more” should be on offer and what concerns me, (apart from the potential of a particular brand of speaker sounding awful, something which, as the manufacturer I wouldn’t be at all happy about) is that the installer neither had any reasonable solution to “running through fabric” to offer, or had the guts to stand by audio quality and insist on running “grilles off”.

Based on the graph above, we supplied an equalizer, pre programmed to offset the response dip, very simply correcting rear cinema speakers, complete with fabric finish. And so, dealing with all issues.

In conclusion I would simply recommend all installers have these items in their tool kits:
pink ear muffs  KONICA MINOLTA DIGITAL CAMERA
Pink ear muffs:  to remind installers that it’s PINK noise often used for audio testing NOT white noise, while ensuring they can’t really hear anything anyway.
Blinkers: to make absolutely sure they can’t possibly see … well, anything really. Not even the obvious.